Synthesis and Characterization of Conductive Polyurethane/Polyaniline (PU/PAni) Films

Yuen, Kar Ee (2020) Synthesis and Characterization of Conductive Polyurethane/Polyaniline (PU/PAni) Films. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Blends of elastic polyurethane (PU) and conductive polyaniline (PAni) were used to improve the electromechanical properties for further applications such as electronic devices and biomedical. In this project, conductive polymer (CP) films based on PU and PAni were prepared via two methods, ex-situ process and in-situ process. The structural characterization and oxidation states of the CP films were confirmed by using Fourier-transform infrared (FTIR) and Ultraviolet–visible spectroscopy (UV-Vis) respectively. UV-Vis spectra significantly proved that pure PAni, PU/PAni (I) and PU/PAni (E) were in conductive emeraldine salt form by showing three main characteristic peaks at π to π*, polaron to π* and π to polaron transition. Furthermore, the thermal and electrical properties were determined in this project. The initial decomposition due to the degradation of PAni and PU hard segments showed the decreasing trend from 307.65oC to 266.22oC while the second thermal degradation temperature (Td) due to degradation of PU soft segments showed increasing trend from 397.61oC to 413.54oC for PU/PAni (E) as PAni content increase. According to Differential Scanning Calorimetry (DSC), the glass transition temperature (Tg) of PU/PAni composites slightly decreased from -36.90 oC to -38 oC with PAni loading (10%, 30% and 50%). In addition, the electrical conductivity of PU/PAni composites also enhanced when the increasing of PAni content in the PU matrix. However, it can be observed that the electrical conductivity of PU/PAni using in-situ method is lower 0.007373 x 10-4 S/cm as compared to the ex-situ method from the range of 0.01846 x 10-4 S/cm to 0.759 x 10-4 S/cm. The reason is the insulating coating of PU may block the conductive pathway of PAni and reduce the conductivity of PU/PAni (I) composite.